Nets for bodies of water

ABSTRACT

A net ( 10 ) for a body of water ( 12 ) that serves to collect flat objects ( 11 ), which are made of foamed plastic and which are saturated with contamination substances, is provided with a catching net part ( 13 ), which can be vertically placed in the body of water ( 12 ) by means of a longitudinally extending sink line ( 18 ) and of a longitudinally extending float line ( 21, 22 ). The aim of the invention is to be able to pull a net of the aforementioned type through the water while tensioned, whereby an upper area of the net always remains above the water surface even in rough water. To this end, the invention provides that the catching net part ( 13 ) is widened by a flexible net part ( 14 ) that, in the area of its free longitudinal edge, is fitted with a longitudinally extending sink line ( 32 ) and is fitted with at least one main float line ( 33 ) between said longitudinal edge and the upper float line ( 21, 22 ) of the catching net part ( 13 ).

The present invention refers to a net for waters to intercept, collect and/or recover flat products, in particular structures consisting of open-cell expanded plastic and soaked with polluting substances, on/from the surface of the water, according to the precharacterizing clause of Claim 1.

Known nets used at sea and, where applicable, also on inland waters are excellent means for catching fish below the water surface; Such nets, so-called fixed nets, are either rigid or flexible in structure, provided with a ballast line below the water surface and an appropriately adjusted float line on the water surface, which causes this fixed net to assume a more or less vertical position in the water. Rigid fixed nets stand in the water similar to a wall and are nearly motionless in the swell of the sea, which results in the waves rolling over the net. In the swell of the sea, while flexible fixed nets move up and down in unison with the waves, big or high waves will likewise roll over the net. However, if flexible fixed nets are tightened by means of a pull rope, they cannot move up and down in the swell of the sea either because they are tightened by the pull rope owing to the water and/or wind pressure involved. Such fixed nets are excellent means for catching fish, as mentioned above, but not for the purpose according to the precharacterizing clause of Claim 1.

In order to intercept, collect and/or recover the flat products soaked with the polluting substance, it is important that the flat products do not move over the net along with the waves, thereby escaping from the collection zone on the water surface.

The objective of the present invention therefore is to create a net of the initially mentioned kind that can be pulled through the water in a tightened manner similar to a fixed net which, however, is allowed to move up and down in unison with the swell of the sea in such a way that an upper part always remains above the water/wave surface even in heavy seas and, therefore, on high waves.

To solve this problem, the features stated in Claim 1 are provided in a net for waters to intercept, collect and/or recover flat products of the initially mentioned kind.

The measures according to the invention ensure that the flexible part of the net is always at a certain level above the water surface even if there are considerable waves in the water. The design of the net results, in a cross-section view, in a roughly tunnel-shaped arrangement of the net in the water, with its basic walls standing upright in the water and its curved intermediate section being located above the water surface and protruding from it by a certain amount. Since the flexible part of the net provides wind and waves only with a little target, it is avoided that the curved part of the net is run over by the waves. Even if this curved part is distorted by the waves, a sufficient portion will still remain above the wave surface, which means that this curved part is practically not rolled over by the waves. This also means that the flat products to be recovered remain in the zone enclosed by said net.

The features according to Claim 2 results in an asymmetric arrangement of the net in the water, which means that the flat products are mainly held by the fixed net part and the flexible net part reacting considerably more quickly can move up and down in unison with the waves. The features according to Claim 3 may be provided there to advantage.

The features according to Claim 4 result in a further support of the measure to ensure that the curved or distorted part of the flexible net part always remains above the water or wave surface, i.e. always protrudes from the water. The features according to Claim 5 are provided there to advantage.

If the features according to Claim 6 are provided, higher stability of the flexible net part in the curved section above the water surface will result. The arrangement of only one net layer in the area of the flexible net part below the water surface can produce higher flexibility. Ease of manufacture will result if the features according to Claim 7 are provided. The fixed net part is designed according to the features of Claim 8 to advantage.

The net described so far consists of a fixed net part and a flexible net part arranged behind it which is put up in a curve above the water surface owing to the design of its free longitudinal edge with ballast and float units. It may happen that the net, which, in a cross-sectional view, looks like a walking-stick, does not withstand all conceivable conditions at sea below and above the water surface such as gale-force storms. In order to avoid the danger that the flexible net part tips over or opens up, the features according to Claim 9 are provided. This results in a net which keeps its desired active position below and in particular above the water surface under all conceivable conditions in the water. This way, stability of said active position of the net is achieved since the flexible net part is kept mainly below the water surface, as this is the case with the longitudinal edge connected to the first fixed net part, by the second fixed net part even at the longitudinal edge distant from the longitudinal edge connected to the first fixed net part. Opening-up or tipping-over of the flexible net part to one side is thus avoided under any given and conceivable conditions.

According to a preferred embodiment of the present invention, the features according to Claim 10 are provided, which additionally prevent the net as a whole from positioning itself mainly flat in the water. The features according to Claim 11 are provided to advantage, resulting in a symmetric position of the net in the water and above the water surface. Another advantage arising from this embodiment with said option consists in the desired position of the net in the water being maintained even if water pressure builds up against the net from both external sides such that only the clear width between the longitudinal edges arranged opposite to each other of the flexible net part and/or of the two fixed net parts is changed.

The design of said embodiment results in greater ease of manufacture of the net provided that the features of Claim 12 are provided.

To facilitate the uncoiling and coiling of the net similarly to conventional fishery nets, the features of Claim 13 are provided. They cause the net to lie flat as it is removed from the water because of the flexibility of the flexible net part while the two fixed net parts position themselves either nearly parallel to the flexible net part or just slightly sagging.

According to another preferred embodiment of the present invention, the flexible net part is designed according to the features of Claim 14. This means that a slack net design as it is used in fishery can be used which can be readily converted to a net part that can be bent to the desired direction. The features according to Claim 15 and/or 16 are provided to advantage. Such flexible solid or hollow bars made from a wide variety of sections such as round sections, rectangular sections, etc. have to be made of plastic, glass fibre, carbon-fibre-reinforced plastic or the like.

The design of the net parts can be further facilitated and the ease of net uncoiling and coiling outside the water is further supported provided the features according to Claim 17 are provided. Unlike where exclusively buoys are used as float units, it is still possible to coil the net flat on a net drum. The features according to Claim 18 and/or 19 may provided to advantage.

The manufacture of the net is further facilitated considerably if the features according to Claim 20 are provided.

Further advantageous net designs result from the features according to one or more Claims 21 to 23.

If the features according to Claim 24 are provided, it will be easy to remove or suck off the soaked flat products.

The present invention moreover refers to a process to remove pollutant layers by means of one or more said nets. For the ease of interception, collection and/or retrieval of such soaked flat products, the features according to Claim 25 are provided.

Advantageous designs of this process result from the features according to Claim 26 or 27.

Further details of the invention can be found in the following description where the invention is described and explained in more detail on the basis of the embodiments shown on the drawing. The figures show the following:

FIG. 1 Typical cross-sectional view of a net for waters according to a first embodiment of the present invention, floating in water,

FIG. 2 Typical partial perspective view of the net according to FIG. 1, in a coilable flat initial state,

FIG. 3 Typical sectional views of nets according to FIG. 1, in various operating states in water,

FIG. 4 A typical view of a unit to place nets according to FIG. 1,

FIGS. 5A-5C Examples of placement of a net according to FIG. 1,

FIG. 6 Another embodiment of one or more placed nets according to FIG. 1,

FIG. 7 Typical cross-sectional view of a net for waters according to a second embodiment of the present invention, floating in water,

FIGS. 8A-8C Partial top views and side views, according to arrow IIB of FIG. 2A, of the net outside the water and in the state in which it can be coiled outside the water, and

FIG. 9 For comparison with the cross-section of FIG. 1, the shape of a net floating in the water and exposed to considerable transverse pressure by the water, in a simplified typical representation.

Net 10, 110 shown on the drawing according to two embodiments of the present invention is destined for waters 12, 112, in particular for seas, and is used to intercept, collect and/or recover flat products 11, 111, in particular of open-cell expanded plastic such as PP or PU or PE open-cell foam, which are soaked with polluting substances such as oily layers, e.g. oil patches, thin layers of oil or liquid plastic, e.g. styrene, as such pollutant layers are removed from the water surface.

According to FIGS. 1 and 2, net 10 has fixed net 13 made of rigid or flexible material and, connected to it, another net part having the shape of grid net 14 and consisting of flexible material which is bending-elastic particularly in transverse direction. Fixed net 13, which is composed of single net layer 16, has ballast line 18, consisting of or containing lead-bearing material, attached to one of its free longitudinal ends 17. At upper longitudinal end 19, which develops into grid net 14 and is connected to the latter, two parallel float lines 21 and 22 are provided between which pull rope 23 is arranged longitudinally and which float on water surface 15.

The only net layer 16 of fixed net 13 develops into net layer 26 of grid net 14 and forms an integral part with net layer 26. Grid net 14 in the embodiment has another two net layers 27 and 28 which lie on net layer 26 and are connected to the latter. The other net layers 27 and 28 form an integral part and are laid out in meanders. It is obvious that net layers 26 to 28 may likewise form an integral part and be laid out in meanders.

Grid net 14, which, like fixed net 13, is provided with, or connected to, float lines 21, 22 and pull rope 23 in connecting or overlapping area 19, has its far free end 31 provided with ballast line 32 which, like ballast line 18, consists of lead or at least partly consists of lead-bearing material. At a distance from this ballast line 32, grid net 14 is provided with a float line unit 33 which consists e.g. of three single float lines and floats on water surface 15. The distance from this float line unit 33 to ballast line 32 of grid net 14 is clearly shorter than its distance from float lines 21, 22 in connecting area 19 of grid net 14 and fixed net 13. Between float lines 21 and 22 in connecting area 19 of fixed net 13 and grid net 14 and float line unit 33 of grid net 14, grid net 14 has further single float lines 36 which are preferably evenly spaced side by side and protrude from water 12 along curved grid net 14.

FIG. 2 shows the design and the flat state of net 10 composed of fixed net 13 and grid net 14 in which state net 10 can be coiled on a drum and uncoiled from this drum 41 on ship 40 and placed in water 12 according to FIG. 4. While being placed according to FIG. 4, net 10, initially being in a flat state according to FIG. 2, takes a tunnel-like shape according to FIG. 1, which is also obvious from FIG. 4. This change in state is a result of the arrangement of ballast lines 18 and 32 and float lines 21, 22, and 33, which cause fixed net 13 and area 34 of grid net 14 between float unit 33 and ballast line 32 to turn upright. It is obvious that the weight of ballast lines 18, 32 is adjusted to related float line 21, 22 and float unit 33. Between vertical fixed net 13 and vertical area 34 of grid net 14, curved section 37 results automatically between float lines 21, 22 and float line unit 33 owing to the bending elasticity of net layers 26, 27, 28. It is obvious that the measure of bending elasticity is dependent on the number and the design of net layers 26, 27, 28.

FIG. 3 is a typical view of how net 10, which has a roughly tunnel-shaped cross-section, moves and behaves under the influence of waves in water 12. Accordingly, curved section 37 is always kept above water surface 15 even under wind and wave attack, as shown with arrow A, and in particular when curved area 37 is distorted. This prevents most of the waves and thus soaked flat products 11 from rolling over.

FIGS. 5 and 6 show how surface zones of polluted water are isolated by means of one or more nets 10. For example, net 10 is subdivided into net sections 43 which are connected to section-shaped hollow part 44 where fixed net 13 and grid net 14 are connected, but are held together directly in the other areas. This way, net 10 consisting of two net sections 43 can, according to FIG. 5B and FIG. 5C, be used by means of ship 40 and buoy 39 or by means of two ships 40 to enclose the affected water zone.

This applies similarly to the embodiment of FIG. 6 where a number of nets 10 each consisting of two net sections 43 and arranged in a V-shape are connected in such a way that they form a barrier against a water zone off coast 45. V-shaped net sections 43 are connected directly to neighbouring ones and are held by anchor 46, for instance, whereas net sections 43 are interconnected by extraction hollow section 44.

According to FIG. 7, net 110 has a first fixed net 113, flexible net part 114 which is integrally connected to it and can put up itself in a curve, and a second fixed net 120 integrally connected to flexible net part 114. Net 110, which is thus composed of first fixed net 113, flexible net part 114 and second fixed net 120 forming an integral part, for instance, is manufactured preferably in the form of a fishing net of slack material known from the fishing technology, in which only the mesh width can be adjusted to the application described above. Net 110 may therefore be one hundred or several hundreds of meters in length as it is common in the fishing technology, its width being different insofar as first fixed net 113, which has a width corresponding to that of fishing nets, is widened by flexible net part 114, on the one hand, and by second fixed net 120, on the other. It is obvious that net parts 113, 114, and 120 can each be manufactured separately and subsequently connected to each other at their longitudinal edges. All net parts 113, 114, and 120 are single-layer net arrangements.

The two fixed nets 113 and 120 have their free lower longitudinal ends 117 and 124 according to FIG. 7 connected to each other and are provided there with common ballast unit 118 taking the form of, for example, a ballast line provided with lead balls. The two joined and connected lower longitudinal ends 117 and 124 are also connected to longitudinal pull line or pull rope 125.

Flexible net part 114, which, considering its active position, will hereinafter be referred to as curved net 114, is elastic, i.e. flexible, over its width owing to the use of flexible bars 150. Flexible bars 150 are preferably and provided evenly spaced over the length of curved net 114. Flexible bars 150 may be firmly connected to curved net 114 at certain distances. Flexible bars 150 may also be threaded through the meshes of curved net 114 so as to achieve an appropriate connection of curved net 114 and flexible bars 150. In this case it is sufficient to connect the ends of flexible bars 150 to curved net 114 e.g. by means of cable ties. For considerations of weight, flexible bars 150 are made of nonmetallic material such as plastic or laminated plastic, e.g. plastic reinforced with glass fibre or carbon fibre. The cross-section of flexible bars 150 may be chosen according to the desired flexibility, for example round, rectangular, oval or the like; they may also be hollow or of solid material or have their cross-section filled in any other fashion desired. The material used is chosen so as not to be affected by pollutant attack.

Curved net 114 additionally has its longitudinal ends, which are connected to the two fixed nets 113 and 120, provided with ballast units 132 and 135 which may be composed of ropes provided with lead balls, for instance. In one area each of curved net 114 distant from the first and second fixed nets 113 and 120, however close to ballast units 132, 135, float units 121 and 133 are provided which, in the embodiment shown, consist of several single extended plastic strips 151 which are arranged parallel to each other. The material provided for these float strips 151 is closed-cell expanded plastic. Five or six such plastic strips 151 are arranged parallel to each other in the embodiment, thus defining float units 121 and 133. Plastic strips 151 are arranged longitudinally to curved net 114 and firmly connected to this net, e.g. threaded through the meshes of curved net 114 alternatingly and kept in place at their ends. It is obvious that other fastening options or arrangements may be provided, e.g. coating of these longitudinal edges of grid net 114 with appropriate expanded plastic. This material is likewise chosen so as not to be affected by pollutant attack.

From the active position of net 110 in water 112 shown in FIG. 7 results a combination of a curve and a V-shape, i.e. the two fixed nets 113 and 120 together are in a nearly V-shape arrangement whereas curved net 114 is curved owing to its transversal flexibility and the ballast and float units used. In addition, the weights of ballast and float units 132, 135 and 121, 133 of net 110 are balanced such that curved net 114 is below water surface 115 starting in the area of float units 121, 133, but is located above water surface 115 with the major part of the curved area.

In the embodiment shown, the two fixed nets 113 and 120 are equal in width whereas, according to FIG. 8B, the width of grid net 114 is either equal to the sum of the widths of the two fixed nets 113 and 120 or somewhat less than the fixed-net widths together. This means that, according to FIG. 8, net 110, when withdrawn from the water, is mainly flat. This is due to the fact that grid net 114 automatically returns to a flat position outside the water owing to its own and the bars' flexibility so that the two fixed nets 113 and 120 being pulled likewise change from their V-shape to a mainly flat position and sag somewhat in relation to flat grid net 114 depending on the relationships of width involved. This shape of net 110 in the so-called dry position allows net 110 to be uncoiled from, and coiled to, a drum easily, which drum may be located on a ship, for instance. This uncoiling and coiling capability is supported by flexible bars 150 being arranged transversely in relation to the coiling direction and plastic strips 151 being designed appropriately to allow the coiling. When net 110 being in this coiled flat state is uncoiled from a drum to water 112, the shape shown in FIG. 1 will result automatically in water 112 owing to the design and balancing or dimensioning of the float and ballast units.

Net 110 in water 112 usually remains in its position as shown in FIG. 1. Only when water pressure builds up at both sides of net 110, which is the case particularly at sea, will net 110 take the cross-sectional shape as shown in the typical view of FIG. 3 without the desired active position of net 110 in water 112 as a whole being changed. The design of net 110 implies that only the V-shape of fixed nets 113 and 120 as well as the curved shape of curved net 114 is changed as a result of compression. This does not affect the use or application of net 110.

The application and use of this net 110 results in the same way as described initially with respect to net 10 in FIGS. 1 to 6.

In an alternative approach which is not detailed here it is possible to choose a greater width for one of the two fixed nets such that the lower longitudinal edge of one fixed net is fixed to an intermediate area of the other fixed net.

To remove pollutant layers such as oily layers, e.g. oil patches, thin layers of oil or liquid plastic like styrene, etc. from water surfaces, flat products 11, 111 consisting of open-cell expanded plastic, e.g. PP or PU or PE open-cell foam, are placed below the water surface so that they can soak the polluting substances on the water surface. To collect and recover the soaked flat products 11, 111, one or more nets 10, 110 being in the flat state are uncoiled from drum 41 on ship 40 and placed on water surface 15, 115, during which process net 10, 110 takes a tunnel shape. Here two or more net sections 43 are connected to each other by means of extraction hollow section 44 and the free ends of outer net sections 43 are connected to buoys 39 and anchor 46 and/or ships 40 by means of pull ropes. One or two ships 40 may circle around the polluted zone on water surface 15 or the net sections may be placed in zigzags off the coast. Soaked flat products 11, 111 are sucked through hollow sections 44 and disposed of or treated in a station. 

1. Net (10, 110) for waters (12, 112) to intercept, collect and/or recover flat products (11, 111), particularly of open-cell expanded plastic soaked with polluting substances, on or from the surface of water (12, 112), with a fixed net part (13, 113) which an be arranged in water (12, 112) mainly in upright position by means of a first longitudinal lower ballast unit (18, 118) and a first longitudinal upper float unit (21, 121), characterized by the fixed net part (13, 113) being widened by a flexible net part (14, 114) which, in the area of its longitudinal edge distant from the fixed net part (13, 113), is equipped with a second longitudinal ballast unit (32, 132) and, between the latter and the first upper float unit (21, 121) for the fixed net part (13, 113), with at least one second longitudinal main float unit (33, 133).
 2. Net according to claim 1, characterized by the main float line (33) being at a shorter distance from the ballast line (32) of the flexible net part (14) than from the float line (21, 22) of the fixed net part (13).
 3. Net according to claim 1, characterized by the distance between the main float line (33) and the ballast line (32) of the flexible net part (14) being considerably shorter than the distance between the float line (21, 22) and the ballast line (18) of the fixed net part (13).
 4. Net according to claim 1, characterized by one or more ancillary float lines (36) being provided between the float line of the grid net part (14) and the main float line (33) of the flexible net part (14).
 5. Net according to claim 4, characterized by the ancillary float lines (36) being evenly spaced between the float line (21, 22) of the fixed net part (13) and the main float line (33) of the flexible net part (14).
 6. Net according to claim 1, characterized by at least a part of the flexible net part (14) being composed of two or more superimposed net layers (26-28).
 7. Net according to claim 6, characterized by the net layers (27, 28) being superimposed in meanders.
 8. Net according to claim 1, characterized by the flexible net part (14) being bending-elastic along its width.
 9. Net (110) according to claim 1, characterized by, along the width of the net (110), a second fixed net part (120) being connected to the longitudinal edge, distant from the first fixed net part (113), of the net part (114) which is flexible along its width.
 10. Net according to claim 9, characterized by the second fixed net part (120) being connected by its free longitudinal edge (124) to the first fixed net part (113).
 11. Net according to claim 10, characterized by the second fixed net part (120) having a width corresponding to the width of the first fixed net part (113) and the free longitudinal edges (117, 124) of the two fixed net parts (113, 120) being connected to each other.
 12. Net according to claim 11, characterized by the first lower ballast unit (118) being common to the two fixed net parts (113, 120) and by a pull line (125) being provided in this connection area of the two fixed net parts (113, 120).
 13. Net according to claim 9, characterized by the width of the flexible net part (114) being equal to or somewhat less than the sum of the individual widths of the two fixed net parts (113, 120).
 14. Net according to claim 9, characterized by the flexible net part (114) being manufactured in a slack net design connected to nonmetallic flexible bars (150) over its width.
 15. Net according to claim 14, characterized by the flexible bars (150) being threaded through the net design.
 16. Net according to claim 14, characterized by the flexible bars (150) being evenly spaced over the length of the flexible net part (114).
 17. Net according to claim 9, characterized by the float units (121, 133) being composed of extended strips (151) preferably of closed-cell expanded plastic.
 18. Net according to claim 17, characterized by the float strips (151) being threaded through the net design.
 19. Net according to claim 17, characterized by several float strips (151) being provided in parallel side by side in each float unit (121, 133).
 20. Net according to claim 9, characterized by the first fixed net part (113), the flexible net part (114), and the second fixed net part (120) being manufactured as an integral unit.
 21. Net according to claim 1, characterized by its capability of being coiled in the flat state.
 22. Net according to claim 1, characterized by its capability of being placed on the water (12, 112) in the flat state.
 23. Net according to claim 1, characterized by a longitudinal pull rope (23, 125) being provided between fixed net part (13, 113) and flexible net part (14, 114).
 24. Net according to claim 1, characterized by an extraction hollow section (44, 144) being provided between two nets (10, 110) in the connecting area of fixed net part (13, 113) and flexible net part (14, 114) and above and/or below this area.
 25. Process to remove pollutant layers such as oily layers, e.g. oil patches, thin layers of oil or of liquid plastic, e.g. styrene, from surfaces of water using flat products or open-cell expanded plastic such as PP or PU or PE open-cell foam, the flat products being placed on the water surface and, when soaked with polluting substances, recovered by means of one or more nets according to claim 1, characterized by the net being uncoiled from a drum in the flat state and placed on the water surface, with two or more net sections being connected to each other by means of an extraction hollow section, and the free ends of the external net sections being connected to buoys or an anchor and/or ships by means of pull ropes.
 26. Process according to claim 25, characterized by one or two ships circling around the polluted zone on the water surface.
 27. Process according to claim 25, characterized by the net sections being placed off the coast in a zigzag manner. 